The association between the Doppler hypoxia index and arterial umbilical cord pH in multiple gestation pregnancies complicated by intrauterine growth restriction

• Published in: Ultrasound in obstetrics & gynecology Vol. 18; no. s1; p. P48
• Main Authors: Musser, U., Gaziano, E. P., Arbeille, P. H.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science, Ltd 01.10.2001
• ISSN: 0960-7692; 1469-0705
• DOI: 10.1046/j.1469-0705.2001.abs27-14.x

Purpose:  To study the relationship between the Doppler hypoxia index and umbilical cord pH in multiple gestation pregnancies complicated by fetal growth restriction. Methods:  Seventeen fetuses were studied from 12 multiple gestation pregnancies (11 twins and 1 triplet). Each pregnancy had at least one growth‐restricted fetus from which middle cerebral artery and umbilical artery Doppler values were collected, the last value of which was within 3 weeks of delivery. For each fetus, we calculated the cerebral umbilical ratio and the hypoxia index, which reflects the duration and degree of Doppler determined fetal blood flow redistribution. Umbilical arterial cord blood was obtained for blood gas analysis immediately after the births. Excluded were fetuses with major congenital anomalies and those with reverse end diastolic flow in the umbilical artery. Results:  There is a significant correlation at the 0.05 level, one‐tailed, between the hypoxia index and arterial umbilical cord pH. A linear regression model suggests that gestational age and birth weights are not cofounders in the relationship between the hypoxia index and arterial pH. While the hypoxia index has the same sensitivity (75%) as the cerebral umbilical ratio for identifying fetuses who will have an arterial cord pH of less than 7.20, the hypoxia index has a better specificity (85 vs. 69%), positive predictive value (50 vs. 38%) and negative predictive value (92 vs. 90%). Conclusions:  There is a significant correlation between the non‐invasive hypoxia index and arterial umbilical cord pH in the growth‐restricted fetus from multiple gestation pregnancies.